DJJ: Nicecast is a workable solution, but it's far from ideal. As for Radioshift Touch, it can't currently tune in to an arbitrary URL, just those found in the Guide. That's likely to change in the future, but it's not there yet.

Bill: A remote for Airfoil is a nice idea, but you need much more than that. You need remote control of both Airfoil ("Send audio to X output", "Lower volume of Y output") and the source it's pulling from ("Play next track in iTunes" or worse "Skip this song on Pandora"). There are a good dozen or two likely sources being used with Airfoil, and hundreds more that are less used but still popular.

While a remote app is a good idea, it's far from simple.